To remove electrical components from a printed circuit board, for example, the solder forming the connection between the component and circuit board must be removed to free the connection. A soldering iron or gun is used to melt the solder and the solder is then withdrawn from the joint while still in the molten state. This may be done with a copper wick, or by a suction tool. An example of a hand-held solder removing tool is described, for example, in U.S. Pat. No. 3,114,026, in which a manually compressed spring is released to drive a piston in a direction to produce a or partial vacuum at an orifice or tip which is applied to the solder joint. The vacuum sucks the molten solder into the tip. Tools of this type provide a single vacuum impulse and then must be manually recocked. This is an awkward and tiring operation where large numbers of soldering joints are being desoldered using this type of tool.
Desoldering guns have been developed which can be held in one hand against the solder joint. The gun is connected through a hose to a vacuum source and a valve in the gun is opened to apply suction to the gun tip when it is needed. Another type of desoldering gun utilizes a venturi-type pump which operates from a source of compressed air. These types of guns have not proved to be entirely satisfactory for several reasons. First, a source of compressed air must be available to operate the device, and the vacuum impulse provided by the venturi is limited in the amount of vacuum that could be produced and the time required to reach peak vacuum.